As a judge you want your contestants to try as hard as they can and do their best, you want to really have a challenge while judging.
As a contestant you want to become a judge, but in order to do so you'll want to try your hardest and do your best.
Here is a compilation of all the judges tips.
This is optional, and if you don't want to post a tip post, that's okay. Contestants can come here for the archives.